Pros: Quiets your bike down 80% because no chain slap. Strong and durable. I've ridden over 100 miles with mine in a lot of mud and creek crossings, rocks flying and been on the ground a few times. This has no rips or signs of wear at all.
Recommendation: Get the right size. Usually bike shops only carry black which was fine for me and it comes clean by spraying it off. Had it off once after 70 miles and no dirt on the inside except traces on each side. Just make sure it's tight on your frame and you will have no problems.
Pros: Once you select the correct size these work great...They need to be removed occasionally to be cleaned.
Cons: The names of the sizes are deceiving. They should have printed the diameter they will fit.
Recommendation: Great product all my bikes have these on them..I tend to stick with black the others get dirty to quickly and stay dirty even after cleaning...I recommend getting the size that you need to stretch it on it will take a few attempts to place it but well worth it the sizes that are too large will tend to move on the stay to much and will collect dirt and scratch...
I personally love these products and will continue to use them on all my bikes.